Control system for electric vehicles.



No. 856.448. PATENTED JUNE 11, 1907.

W. COOPER. CONTROL SYSTEM FOR ELECTRIC VEHICLES.

APPLICATION FILED 0073.3. 1906.

WITNESSES: INVENTOR WM Y - 7 ATTORNEY UNITED strains PATENT orFIon.

WILLIAM COOPER, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WEST- INGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CONTROL SYSTEM 'Fon eLEc'rmo VEl -HCLENS.

V Specification of Letters Yatent.

'latented Jun 11,1907.

Application filed October 3, 1906. Serial No. 387.289.

To all whom it may concern: i

Be it known that I, WILLIAM COOPER, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Systems for Electric Vehicles, of which the following is a specification. Y

My invention relates to systems of electric motor control and particularly to systems of this class which are adapted for the control of electric vehicles having a plurality of similar driving motors.

The object of my invention is toprovide means for automatically interrupting the suppl of ener y to the motors of an electric ve ic e upon the occurrence, for any reason,

iofa material difference in the motor speeds.

Whenelectric vehicles, having two or more driving motors which are severally geared or otherwise connected to the driving axles of the vehicle trucks, are started on a grade or under other severe load conditions, one pair of vehicle wheels sometimes slips so that the speed of its driving motor is materiallyincreased above that of the other motors. As the speed of-one of the motors is thus increased, the counter-electromotive force of the circuit in whichit is connected is mate: rially augmented sotha't the current is decreased and the 'tractive eflo'rt exerted by the vehicle is seriously diminished. In order thatthe motors may againexert a maximum torque,'it is desirab e to interrupt the supply of energy thereto and temporarily re-insert such ortions of resistance as'had been exclude from the circuit in'accelerating the motors before the slipping occurred.

Accordin to m present invention, 1 provide means epen ent upon a material difference in the s code of the several motors for. automatically interru ting the supply' of energy to the motors ,0 an electric ve ic e.

The single figure of the accompanying drawing is a diagrammatic view of a system of electric vehicle control arranged in-accordance with my invention, which embodies two similar electric drivin motors that are controlled by a plurality electric switches and are equipped with means whereby auto-v determine the direction of rotation of the matic acceleration may be effected.

by contact finger 26. From contact As illustrated in the drawing, a .diflerential relay is provided which comprises amovable contact bearing member sitely wound magnet windings therefor which are respectively connected across the armatures of the two vehicle motors, and a bridging contact member which interrupts the control circuits of the system Whenthe two similar magnet windings are unequally energized.

is adapted to occupy a plurality of positions a, b, a: and ,1 and through which energy may be supplied to the acuating coils of the switches from a battery 11.

The direction of rotation of the armatures of the motors is determifed by a plurality of reversing switches 12, 1d, 14-, 15, 16, 17, 18 and 19. lTJhen the master controller is moved from its ofi position to the position a, in which automatic acceleration is permitted, energy is supplied from the battery 11 through a contact finger 20 to contact ring segments 21 and 22 which are first engaged by a plurality of fingers 23 and 24, the contact ring segment 22 being finally en aged hnger 23, energyis supplied through conductor 27 to the actuating coil of the switch 28 and the circuit is completed from this point through a conductor 29, contact fingers 31 and 32, which are normally connected by bridging contact member 33, and a conductor 34 to the negative terminal of the battery 11. From the contact finger 24, ener y is supplied through a conductor to the actuating coils of the switches 12, 15,- 17 and 18 which two similar oppo- The action of these switches is determined by a master controller 10 which l motors, a circuit being similarly completed from each of these coils through the battery negative conductor 29. I 4

Energy is supplied from the contact finger 26, through a conductor 37 and through a bridging contact member 38, which is located on a switch 39 and is engaged by a pair of contact fingers 40 and 41 when said switch is in its open circuit position, to the actuating coil of a switch 42, from which point the circuit is completes to the battery negative conductor 29. lhe aforesaid actuating coils being energized, theswitches 28, 12, 15, 1.7, 18 and 42 are closed and, consequently, a circuit is completed from the line conductor 9 through switches 28 and 12, armature 1, switch. 15, field magnet winding 5, magnet coil 43 of a switch 52, resistance sections 47 and 43, switch 42, resistance sections 49 and 50, field magnet winding 7, switch 17, armatime 4, switch 18 and conductor 3 to an oppo site line conductor 51. Thus it will be observed that the motors are first connected in series relation, with resistance sections 47, 48, 49 and 50 included in circuit therewith. When the switch 42 is first closed, the current flowing in the motor circuit is usually sufficient to open a switch 52 having an actuating magnet winding 42, thereby temporarily suspending the automatic acceleration until the counter-electromotive force of the motors has sufiicientlyincreased with their s eed to reduce the current flowing in the circuit and to permit the switch 52 to close.

When the'switch52 is closed, a circuit is completed from contact finger 23 through conductor 35, switch 52, conductor 36, contact fingers 56 and 58, which are connected by ring se ment '57 when the controller 10 occupies eit er position a or position at, conductor 59, contact fingers 60 and 61, which are engaged by bridging contact member 62 when the switch 42 is closed, conductor 63, contact fingers 64 and 65, which are engaged by bridging contact member 66 when a switch 67 is open, and through the actuating coil of the switch 67 to the battery negative con ductor 29.

When the switch 67 is closed, the contact finger 64 is disengaged from the bridging contact member 66 and moves into enga ement with contact member 69, which is a 0 engaged by a contact finger so that the accelerating circuit is now continued from the finger 64, through the contact member. 69 and contact finger 70 to a contact finger 7 1 of a switch 72, to short-circuit the'resistance section 48. The contact member 66 of the switch67 now engages contact finger 65, and

also a contact finger 73 that is sup lied with energy directly from the con uctor 27.

as see lee this osition, irrespective of the limiting switc 52, since its operating coil is now supplied with energy directly from the positive terminal of the battery through the master controller.

The steps involved in the closure ol the switch 67 are repeated for the switch 7 2 and for a -lurality of switchesi'7 7 and .78 which are a apted to short-circuit resistance sections 50 and .49, the first step in the operation of each switch being dependent upon the limiting device.

XV hen switch 78 is closed, the motors connected across the line with substantially no external r switch 39 is net closed/energy being supplied to its actuating coil through a con ductor 79, contact finger 80, bridging contact member 81, contact finger 82, contact fingers 83 and 84 oi a switch 85, which are engaged by a bridging contact member 36 when said switch is open, conductor 87 and, through the actuating coil of the switch 39, to the battery negative conductor 29.

As soon as the switch 39 is closed, the actuating magnet of the switch 42 becomes deenergized by reason of the dis-engagement oi the contact fingers 40 and 41 from the bridging contact member 38. Furthermore, contact fingers 74 and 75 become dis-engaged from the bridging contact member 76 so that the circuit which has supplied energy for holding the switches 67, 72, 77 and 7 8 closed, is interrupted, and the switches are opened. The motor circuit is now completed, from the coil 43, through switch 39 to field magnet winding 8 so that the circuit connections of the motors remain the same, except that a single shunt short-circuits the sections of resistancc, instead of the several shunts as hereinbefore indicated.

When the switch 42 is opened, contact fingers 60 and 61 are dis-engaged from bridging contact member 62. The circuit from the conductor 59 is now continued through contact fingers 88 and 89, which have moved into engagementwith a bridging contact member 90, and energy is sup lied to the actuating coils of switches 91 an 85. These coils are thereafter immediately transferred in a well known manner from the accelerating circuit to a holding'circuit which is independent of the limiting device. I

As soon as the switch is closed, the contact fingers 83 and 84 become dis-enga ed from the bridgin contact member 86 so t at the actuating c011 of the switch 39 is deenerizedand the switch is permitted to open.

ircmt is now completed from the "line conductor 9 through armature 1, field magnet d ng 5, coil 43 of the limiting switch 52, resistance sections 47 and 48, and'switch -91 to the opposite line conductor 51. Energy is also supplied from the line conductor 9 through switch 85, resistance sections 49 and l istai'ice the circuit. The

50, field magnet windin 8 and armature 3"to the opposite'line con uctor 51. The two motors are thus connected in parallel circuits. When-the switch 85 is closed, a plurality of contact fingers 92, 93 and 94 move into engagement with a bridging contact member 95, so that energy is supplied to finger 64 of the switch 67 and also-to the corresponding contact finger of the switch 77. Consequently, the-switches 67 and 7 7' are simultaneously closed subject to the action of thelimiting switch 52, and suitable connections for closin the'switches- 72 and 78 are efieoted. in this way, the resistance included in each of the multiple circuits containing the motors is simultaneously decreased 'to zero and the motors are connected directly across the'line- W hen the controller 10 occupies theposition m, circuits are established similar to those which correspond to the position a except that, instead of the reversing switches 12, 15, 17 and .18 bein closed, the switches 1'3, 14,- 16 and 19 are c osed'so'that the current traversing the motor circuit passes through the armatures of the several motors in the opposite direction. If it is desirable, any stage of the acceleration of the motors, to revent anincrease in the speed of the vehis e, the master controller 10 may be moved from the position a to the position b or'trom thepositionit to the position 9 as the case 'may he, in which positions the contact fin.

from thegers 56 and 58 become dis-engaged contact ring segments 57 and it is impossible to supply energy to the conductor 59 from which tne emanating coils of the several switches first receive their energy. The switches already closed, however, will he re tained in such position since all the other cirsuits are uninterrupted.

it is-desirahle to stop the equipment or to interrupt the supply of energyto the motors, the controller 10 may be moved to the oil position, when all the switches will he opened.

in order to automatically interrupt the V supply of energy to the motors in case their speeds become materially difierent, a differential relay 44is included in the battery circuit. This relay comprises a contact bearing core member 45 and similar magnet windings 46 and 53 which are respectively connected across the armatures oi motors 1 and't and are so arranged that their magnetizing'ei-- *Eccts upon the core member 45 normally neutralize each other since the electromotive forces at the armatures of the two inotorsare normally equal. If. the s eed of one of the motorsshould be materially increased above thatof the other, as is the case when the pair of wheels to which one of the motors is connected slips, the electromotive force'applied to one of the windings on the differential relay-44 willbegreater than=that applied to the other and the'oore-lfi-will be so ener zed as to raise the contact member 33 which ridges thecontact members 31 and 32. As soon as the battery'circuit is-interru ted at this point, the control-switches will all e opened, thereby interrupting theysupply of energy to the motors and necessitating theirre-acceleration; This re-acceleration will automatioally take place a's-soon. as the. speeds of the .motors are again balanced if the master controller still occupies either the position a or a the position 12:.

lclaim-as my invention: 1. In a vehicle, the combinationwith'driving motors therefor, of means dependent upon a material difference in the motor speeds for automatically interrupting the simply of energy to the motors.

2. in a control system for'electric vehicle motors, the combination with a plurality of electrically governed switches, of means dependent upon a material difi'erence in motor speeds for automatically opening said switches. 3. in an electric vehicle, the com with a plurality of drivingrnotormcf 1 cans dependent upon a material diflerence the electromotive forces. existing acr ss 1 motor armatures for automatie l vinreprin the supply of eneKgy to tliemot -s.

in a control systern for electric v the CGfilblllMJIOll with a plurality o and governing switches therefor, oi nnes-ns-"t pencent upon a' material difference speed of the motors for automatically'open ing the switches.

5. in an electric vehicle, the combination with electric driving motors, and aplurality of governing switches for the motors, of a differential relay which is adapted to effect the opening of the switches and is provided the with similar opposing co'ilsthat are severally connected to the motor armatures.

in a control system for electric vehicles, the combinationwith a. plurality or electric driving motors, a plurality of goverm'ng switches therefor, a master switch for con.- trolling the govern ng switches, and pinrality of actuating magnets for said switches,

of a differential relay that comprises core member, a plurality of similar opposing coils whichare severally connected across t e armatures of said driving motors, and means dependent upon a material difierence in the speeds of the motors for automatically interrupting the supply of energy to the actuating coils of the governing switches.

-7. In a control system for e ectric vehicles, the combination with a plurality of electric driving motors, a plurality of governing switches therefonfa master switch for controlling'the-governingswitches, and a pinrality of actuating magnets for said switches,

differential relsy that comprises core of a .rnemher, e plurality of similar opposing coils which are severally connected across the an matures of said driving motors, and means dependent upon a material difference in the energizing currents for the coils of the dii'lerential' relay for automatically interrupting the supply of energy to the actuating coils of the gover switches. I

8. In an e ectric vehicle, the combination with electric driving motors and control switches therefor that are adapted to he closed in the predetermined'sequence, of a dihferentiel relay adapted to effect the opening of the switches and comprising similar magnet windings which ere severally connected in multiple circuit with the motor armature to normally act in op osition to each other. I

9. In an electric ve' 'icle, the combination with electric driving motors, a plurality of electrically operated governing switches therefor which are adapted to close in sequeues, and an auxiliary source of energy for efiecting the closure of the switches, of means dependent upon a material diflerence in the motor speeds for automatically interrupting thesupply of energy to the switches from supply of energy to the witl'zhes'"from said aurzuhsry source.

11. In an electric vehicle, the combination "ith electric driving motors, a plurality of electrically operated governing switches therefor which are adapted to close in a predetermined sequence, and an auxiliary source of energy for effecting the closure of the switchesmr" a differential relay adapted to interrunt the supply of energy to thegoverning switches and comprising similar ma -net windin s which are severally connecteo in multipe circuit with the motor armatures to act in' opposition to each other.

12. In an electric vehicle, the combination with electric driving motors, a plurality of electrically operated governing switches therefor adapted to close in sequence, and an auxiliary source of energy for: effecting the closure of the switches, of means dependent upon a material dificrence in the motor speeds for automatically interrupting the supply of energy to the switches from said auxiliary source comprisii an electrically operated relay switch having two similar windings that are connected in multiple circuit with the motor armatures and set in opposition to each other, and a movable core member which normally bridges the auxilisry control circuits of the eoyernin switches.

In testimony whereof, lhave hereunto subscribed my name this 28th day of September,

, WILLIAM CUUPER. Witnesses:

Howann L. Berton, Burner Hmns. 

